Spinneret for producing trilobal yarns

ABSTRACT

The invention discloses a spinneret for producing a trilobal filament, and filaments produced using such spinneret. The shape of each orifice of the spinneret can be considered as being produced by a circular aperture, diameter D into which project at 120* intervals, three identical triangular portions, sides of the triangles being tangent to one or more coaxial circles having a diameter between one-sixth and one-third of D, the angle at the apex of each triangle being between 60* and 100*.

United States Patent Jacquinet Feb. 15, 1972 [54] SPINNERET FOR PRODUCING [56] References Cited IL TR OBAL YARNS UNITED STATES PATENTS [72] Invent Jean'umis Jacqune" 3,097,416 7/1963 McKinney ..161/177 x [73] Assignee: Societe Rhodiaceta 3,419,936 1/1969 Sims ..18/8 SS [22] Filed: y 25 1970 3,478,389 11/1969 Bradley et al ..18/8 SS 21 L 41,1 2 Primary Examiner-J. Spencer Overholser Assistant Examiner-Michael 0. Sutton Related US. Application Data AtrarneyCushman, Darby & Cushman [62] I3)i5v7is,io6n2i5)f Ser. No. 670,862, Sept. 27, 1967, Pat. No. [57] ABSTRACT The invention discloses a spinneret for producing a trilobal [30] Foreign Application Priority Data filament, and filaments produced using such spinneret. The

shape of each orifice of the spinneret can be considered as Sept. 29, France being produced y a circular aperture diameter D into which Aug. 11, 1967 France ..1 17816 p j at 0 intervals, three identical triangular portions,

sides of the triangles being tangent to one or more coaxial cir- [52] US. Cl ..425/465, [61/177 cles having a diameter between one sixth and one thi|-d of D, [51] Int. Cl. ..D0ld 3/00 the angle at the apex of each triangle being between 0 d [58] Field ofSearch ..18/8; 264/177 R, 177 F;

1 Claims, 4 Drawing Figures Pmm ms I972 3.642.420

SHEET 1 0F 2 In venlor A Uorn ey;

PATENTEHFEB 75 I972 SHEET 2 0F 2 A Uorneys SPINNERET FOR PRODUCING TRILOBAL YARNS This application is a division of my copending application, Ser. No. 670,862, filed Sept. 27, 1967 and now U.S. Pat. No. 3,579,625.

The present invention relates to spinnerets for producing trilobal filaments.

It is already known in the textile industry toemploy spinnerets in which the orifices have noncircular shapes, such as the triangular, square, rectangular or arcuate shapes with a view to obtaining yarns the cross section of which is a special shape differing from the conventional round or substantially round shape of the majority of artificial and synthetic yarns. These yarns may for example have cross sections having the shape of a clover loaf, the letter Y, the letter X, the letter H or the letter C, or they may be substantially flat or hollow.

lt is an object of the present invention to provide a spinneret for producing filaments having anovel and improved cross section.

It is a further object of the present invention to provide a spinneret comprising at least one spinning orifice, each spinning orifice being defined by, in combination:

a. three identical arcuate portions of a first circle, of diameter D, said portions being disposed 120 with respect to one another;

b. two ends to each said arcuate portion;

three pairs oflines; a first line of each pair extending inwardly of said circle from one end of one of said arcuate portions; e. a second line of each pair extending inwardly of said circle from the other end of the arcuate portion adjacent to said one arcuate portion;

inner circle concentric with said first circle, the second lines of the pairs of lines being tangential to said one or another inner circle concentric with said first circle, the diameter d of said inner circle or circles lying between one-sixth and one-third of the diameter D of said first circle; and

g. said first line of each pair intersecting said second line of an adjacent pair at an angle a of between 60 and 100.

It is still a further object of the present invention to provide a spinneret for producing a yarn comprising at least one trilobal filament, the cross section of which is substantially that of an equilateral triangular core, and three substantially congruent triangular lobes, one apex of each of the lobes being coincident with a separate one of the apices of the core, and one side of the triangular lobe lying substantially along a side of the triangular core.

The polymers utilized in carrying out the invention include cellulose esters such as cellulose acetate or cellulose triacetate, or they may be synthetic polymer such as polyhexamethyleneadipamide which can be melt spun, provided that the extruded filaments are cooled suddenly.

The spinneret of the invention may be utilized with any known device for dry or melt spinning. A spinneret furthermore may have any shape and any desired dimensions being made from any material which is appropriate, having regard to the material which is to be spun. It may for example be plate shaped or cup shaped, and the orifices may be disposed in one or more rings, or in one or more lines.

For use in the manufacture of cellulose ester filaments according to the invention, the temperature of the spinning chamber walls should be between 80 and 130 C., depending on the nature and volatility of the solvent utilized and on the duration of the stay of the filaments in the chamber, i.e., in accordance with the spinning velocity and the length of the chamber.

The special cross-sectional shape of the filaments produced according to the invention impart special properties to them, in particular a high degree of resilience, this being a quality which is particularly desirable and appreciated in carpet pile and in other uses which necessitate a fiber of extremely high bulk. The special cross-sectional shapes may also be of interest when it is desired to produce an article having a special the first lines of the pairs of lines being tangential to one appearance. Other features and objects of the invention will become apparent from the following detailed description given merely by way of example, reference being made to the accompanying drawings, in which:

FIG. 1 is an underneath plan view of one embodiment of spinneret according to the present invention;

FIG. 2 is an enlarged schematic view of one of the orifices of the spinneret of FIG. 1;

FIG. 3 shows, to a considerably enlarged scale, the cross section of a yarn formed from five cellulose ester filaments extruded through a spinneret having five orifices the shape of each of which is as illustrated in FIG. 2; and,

FIG. 4 shows, to a considerably enlarged scale, the cross section through a yarn comprising three synthetic polymer filaments extruded through a spinneret having three orifices the cross section of each of which is as illustrated in H0. 2.

Referring now to the drawings, there is illustrated in P10. 1, a spinneret 10, according to the invention, having nine orifices 11 disposed in a circular array concentric to said spinneret.

Each said orifice ll of the spinneret has the cross section illustrated to an enlarged scale in the schematic FIG. 2. Each orifice is thus essentially a circular orifice 12 into which project three triangular inserts 13, 14 and I5, spaced apart around the circumference of the circle 12, which has a diameter D.

Triangles l3, l4 and 15 are identical or congruent, and each includes two straight sides 13A, 13B; 14A 14B; and 15A, 158, respectively. The sides 13A, 14A and 15A are all, as can be seen from the Figure tangents to smaller circle 16, which is concentric to circle 12, and has a diameter d. The diameter of circle 16 lies between one-sixth and one-third the diameter D, of circle 12. The lines 13B, 14B and 15B are also tangents to the small circle 16, or to another circle (not shown) the diameter of which also lies between one-sixth and one-third of the diameter, D of circle 12. Each of these pairs of lines join at an angle a, which lies between 60 and 100. The orifice thus formed can thus be considered to be defined by three arcuate portions 17, I8 and 19, of the circle 12, and by the three pairs oflines 13A, 13B; 14A, 14B; and 15A, 158. I

In use, the spinneret may be secured to the top of a vertical spinning chamber (not shown) the walls of which may be provided with heating means to heat such walls to a suitable operating temperature. The following examples illustrate the use of the spinneret in the production of trilobal filaments according to the invention EXAMPLE 1 A solution was prepared in acetone, containing 27.5 percent of secondary cellulose acetate. This solution was extruded into a vertical dry spinning chamber, the walls of which were heated to C. through a spinneret formed with nine orifices as illustrated in FIG. I, i.e., arranged in a ring.

Each orifice had the following parameters:

D==0. l 8 millimeters d=0.04 millimeters (i.e., 2/9 D) Ambient air was caused to circulate in the spinning chamber downwardly in the same direction as the yarn, and acted as an evaporation atmosphere. At the bottom of the chamber, a denier 167 decitex) nine filament yarn, was recovered at a velocity of 250 meters per minute, the cross section of each of the filaments of which was similar to that of each of the five filaments illustrated in FIG. 3. A number of such yarns may be combined to form a tow suitable for the manufacture of cigarette filters or carpets, or for cutting up in order to produce staple fiber.

EXAMPLE 2 same parameters as in Example 1, into a dry spinning chamber, the walls of which were heated to 85 C. Air was circulated downwardly as before and a 135 denier (150 decitex) nine filament yarn was obtained at a velocity of 200 meters per minute. The yarn obtained included filaments which each had a cross section similar to the cross section of the individual filament illustrated in FIG. 3. The yarn was extremely bulky, and was suitable for manufacturing extremely bulky articles. It was also possible to assemble a multiplicity of identical yarns in order to form a tow as in Example l.

EXAMPLE 3 A solution was prepared in acetone, containing 27.5 percent of a secondary cellulose acetate. The said solution was extruded through a spinneret having five orifices, each of which was identical with the orifice of Example 1, and the same dry spinning chamber was used as in Example 1, the walls however being heated to 1 15 C.

The evaporating atmosphere, consisting of ambient air, was circulated in the chamber downwardly and in the same direction as the yarn. A 100 denier l 1 1 decitex) five filament yarn, having the cross section illustrated in FIG. 3, and of the bulky appearance, was obtained at a velocity of 200 meters per minute.

EXAMPLE 4 A solution identical to that of Example 3 was extruded through a spinneret formed with 36 orifices which were homothetic with those of Example 1, but having a section ratio of 1:4 into a chamber identical with that of Example 1, but the walls of which were heated to 120 C. and through which the evaporating atmosphere again flowed in a downward direction.

A 200 denier (222 decitex) 36 filament yarn, having a cross section similar to that shown in FIG. 3 which was bulky, and of good resilience, was obtained at a velocity'of 300 meters per minute.

EXAMPLE 5 A polyhexamethylene adipamide, the relative viscosity of which was 35, measured at 25 C. in an 8.4 percent solution in 90 percent formic acid was extruded at a temperature of 292 C., under a pressure of 14 kilograms per square centimeter under nitrogen through a spinneret formed with 180 orifices having the shape shown in FIG. 2, each orifice having the following parameters:

D 0.54 millimeters d=0.1 1 millimeters (d=D/5) The filaments were extruded at a velocity of 40 meters per minute into a bath of cold water disposed 6 centimeters below the spinneret and were cold drawn at a rate of 3. A 3,120 denier (3,470 decitex) yarn each of the 180 filaments of which had approximately the cross-sectional shape shown by each of the elements in FIG. 4, was obtained.

The above Example 5 illustrates the preparation of polyamide filaments. It will be readily apparent to those skilled in the art that the spinneret of the present invention is suitable for use with other synthetic polymers such as polyesters or polyolefines.

As can be seen from FIG. 4, the shape of each individual filament can be analyzed into that of four adjacent triangles.

The core of the filament essentially comprises an equilateral triangle ABC and the lobes of the filament comprise three identical or congruent lobe triangles ADE, BFG, and CH]. Eachof the lobe triangles has one of its apices coincident with an apex of the equilateral core triangle. EAch side of the core triangle forms a portion of the side of one of the lobe triangles.

The filament has a cross section derived from the form of the orifice i.e., a form inscribed in that of the orifice and having rounded corners particularly at the extremities of the lobes.

We claim:

1. A spinneret comprising at least one spinning orifice, each spinning orifice being defined by, in combination:

a. three identical arcuate portions of a first circle, of diameter D, said portions being disposed with respect to one another;

b. two ends to each said arcuate portion;

c. three pairs of lines;

d. a first line of each pair extending inwardly of said circle from one end of one of said arcuate portions;

e. a second line of each pair extending inwardly of said circle from the other end of the arcuate portion adjacent to 

1. A spinneret comprising at least one spinning orifice, each spinning orifice being defined by, in combination: a. three identical arcuate portions of a first circle, of diameter D, said portions being disposed 120* with respect to one another; b. two ends to each said arcuate portion; c. three pairs of lines; d. a first line of each pair extending inwardly of said circle from one end of one of said arcuate portions; e. a second line of each pair extending inwardly of said circle from the other end of the arcuate portion adjacent to said one arcuate portion; f. the first lines of the pairs of lines being tangential to one inner circle concentric with said first circle, the second lines of the pairs of lines being tangential to said one or another inner circle concentric with said first circle, the diameter d of said inner circle or circles lying between onesixth and one-third of the diameter D of said first circle; and g. said first line of each pair intersecting said second line of an adjacent pair of an angle Alpha of between 60* and 100*. 